High Frequency Deep Brain Stimulation Reduces Exaggerated Synchronization in Biophysically Realistic Spiking Neural Networks

Synchronization in neuronal ensembles plays an important role for information transfer in the brain, though its exaggeration is a neurophysiological marker of common brain disorders such as Parkinson’s disease (PD). Deep brain stimulation (DBS), a clinically established therapy for PD, delivers electrical pulses at high frequencies to deep brain regions and is known to reduce the high amount of synchrony.

To further investigate DBS effect on the spiking activity of neuronal populations, using Morgera’s index of synchronization (MI), first we evaluated the effect of stimulation on the coupled rhythm of two excitatory (E) and inhibitory (I) neurons. Then, we extended the analysis to two E and I neuronal populations coupled with random and small-world connections and varied the stimulation frequency to examine its effect on the spiking patterns and network dynamics. 

At stimulation frequencies higher than ~90 Hz MI was reduced at both bicellular and network systems. Low frequencies (< 40 Hz) produced higher MI, resulting in resonance. 

The methods in this study serve as biophysically realistic building blocks of DBS network models, and MI was seen to be a promising measure for network synchronization. The results were robust towards the topology of the networks, providing us with insights into DBS mechanisms of action at both cellular and network levels.